Ephedrine is a stimulant drug, a close chemical relation to methamphetamine albeit with less strong effects. It is not (yet) illegal, but the powers that be are working on it, with the excuse that it can be a chemical precursor in methamphetamine manufacturing. (A single oxygen atom is the difference between ephedrine and meth, though the former's isomer, pseudoephedrine (an ingredient in over the counter cold remedies) is more often used for this purpose.) Buy it now while you still can!
 Effective for
Ephedrine is a bronchodilator and so is effective as a temporary over the counter remedy for asthma. It is also effective as a stimulant and is sometimes sold in truck stops to truck drivers for this purpose. Because it is a methamphatetamine precursor, its sales in truck stops have been severely curtailed since 2006 due to the U.S. federal law requiring buyers show I.D. and sign for their purchase. Most such stores don't want to bother with the red tape. It is still easily available in pharmacies under the Primatene Tablets, Bronkaid, DMD Pharmaceutical and other brand names as an asthma remedy, though (if you don't mind showing I.D. and signing for your purchase.)
Purchasers of ephedrine are now limited to the same monthly legal limits as also applies to pseudoephedrine cold remedies such as Sudafed. Some individual U.S. states have made both ephedrine and pseudoephedrine prescription-only, while others have not. Some misinformation continues to circulate on the Internet that ephedrine itself is banned completely in the U.S. or is prescription-only at the federal level. Both are still untrue as of 2011.
 Not effective for
It was also used usually in combination with caffeine in "diet pills" (for which anecdotal evidence isn't lacking, but empirical evidence is) until the FDA put a stop to the practice. Its use as a "performance-enhancing drug" is banned by the International Olympic Committee. An urban legend persists among bodybuilders that ephedrine, caffeine, and aspirin taken in combination (the ECA stack) burns off fat or turns fat to muscle. (Another chemically related over the counter asthma remedy, clenbuterol—illegal in the United States because its use by farmers to keep cattle and pigs thin results in toxic levels of the drug building up in the meat—has a similar reputation as a fad diet and bodybuilding drug and is obtained through gray-market channels from Europe, where it is legal.)
Since the FDA ban on the inclusion of ephedrine mixed with caffeine in purported diet and bodybuilding pills, marketers have switched to synephrine in conjunction with caffeine as the active ingredient. Synephrine has some similar effects to ephedrine, with more pressor effects and less central effects, but is not a methamphetamine precursor. It does, however, carry the same safety concerns over reported adverse effects.
 Safety concerns
The herb ephedra (also known as ma huang or Mormon tea), illegal to sell in the United States since 2004 per an FDA ruling, contains naturally occurring ephedrine, pseudoephedrine, phenylpropanolamine, and several other substances. The ban only applies to the herb ephedra, and not to pharmaceutically-manufactured ephedrine. Ephedra was deemed not safe by the FDA because of the combination of substances occurring naturally (including phenylpropanolamine, also banned by the FDA) and several reported adverse effects; although the FDA took little notice of it until one enterprising type started marketing it mixed with caffeine as "Herbal Ecstacy" during the late 1990s, leading to kids overdosing on it. The herb ephedra may contain wildly varying amounts of ephedrine and the other psychoactive chemicals, making accurate dosing difficult.
Purported diet and bodybuilding pills containing a mix of ephedrine and caffeine have also had many reported adverse effects, from heart palpations to stroke. Ephedrine and caffeine are both stimulants and multiply the effects of each other.
Ephedrine gained a reputation during the 1980s as legal "trucker speed," following the rise of mandated drug testing for drivers during the Ronald Reagan administration which caused the formerly widespread use of Benzedrene and other amphetamines to end; this led to its use at decidedly off-label dosages or in conjunction with caffeine.